Magnetoresistance effect element, magnetic head and magnetic recording and/or reproducing system

ABSTRACT

There is provided a practical magnetoresistance effect element which has an appropriate value of resistance, which can be sensitized and which has a small number of magnetic layers to be controlled, and a magnetic head and magnetic recording and/or reproducing system using the same. In a magnetoresistance effect element wherein a sense current is caused to flow in a direction perpendicular to the plane of the film, if a pinned layer and a free layer have a stacked construction of a magnetic layer and a non-magnetic layer or a stacked construction of a magnetic layer and a magnetic layer, it is possible to provide a practical magnetoresistance effect element which has an appropriate value of resistance, which can be sensitized and which has a small number of magnetic layers, while effectively utilizing the scattering effect depending on spin.

CROSS REFERENCE TO RELATED APPLICATION

[0001] This application is based upon and claims benefit of priorityfrom the prior Japanese Patent Applications No. 2000-275417, filed onSep. 11, 2000; the entire contents of which are incorporated herein byreference.

BACKGROUND OF THE INVENTION

[0002] 1. Field of The Invention

[0003] The present invention relates generally to a magnetoresistanceeffect element, a magnetic head and a magnetic recording and/orreproducing system. More specifically, the invention relates to amagnetoresistance effect element using a spin-valve film wherein a sensecurrent flows in a direction perpendicular to the plane of the thinfilm, a magnetic head including the magnetoresistance effect element,and a magnetic recording and/or reproducing system including themagnetoresistance effect element.

[0004] 2. Description of Related Art

[0005] There is known a phenomenon that an electric resistance varies inresponse to an external magnetic field in a certain kind offerromagnetic material. This is called a “magnetoresistance effect”.This effect can be used for detecting an external magnetic field, andsuch a magnetic field detecting element is called a “magnetoresistanceeffect element (which will be hereinafter referred to as an “MRelement”)”.

[0006] Such an MR element is industrially utilized for readinginformation, which has been stored in a magnetic recording medium, in amagnetic recording and/or reproducing system, such as a hard disk or amagnetic tape (see IEEE MAG-7, 150 (1971)), and such a magnetic head iscalled an “MR head”.

[0007] By the way, in recent years, in magnetic recording and/orreproducing systems utilizing such an MR element, particularly in harddisk drives, the magnetic recording density is being enhanced, and thesize of one bit is decreasing, so that the amount of leakage flux from abit is increasingly decreased. For that reason, it is necessary toprepare an MR element, which has a high sensitivity and a high S/N ratioand which can obtain a high rate of change in resistance even in a lowermagnetic field, in order to read information which has been written in amagnetic medium, and this is an important basic technique for improvingthe recording density.

[0008] The “high sensitivity” means that the amount of change inresistance (Ω) per a unit magnetic field (Oe) is large. As an MR elementhas a larger amount of change in MR and a more excellent magneticallysoft characteristic, the MR element has a higher sensitivity. Inaddition, in order to realize a high S/N ratio, it is important toreduce thermal noises. Therefore, it is not desired that the resistanceitself of the element is too high, and when the element is used as areading sensor for a hard disk, the resistance of the element ispreferably in the range of from about 5 Ω to about 30 Ω in order torealize a good S/N ratio.

[0009] Under such a background, at present, a spin-valve film capable ofobtaining a high rate of change in MR is generally used as an MR elementfor use in a hard disk MR head.

[0010]FIG. 19 is a conceptual drawing showing an example of a schematiccross-sectional structure of a spin-valve film. The spin-valve film 100has a structure wherein a ferromagnetic layer F, a non-magnetic layer S,a ferromagnetic layer P and an antiferromagnetic layer A are stacked inthat order. Of the two ferromagnetic layers F and P which aremagnetically in a non-coupled state via the non-magnetic layer S, themagnetization of one ferromagnetic layer P is fixed by an exchange biasor the like using the antiferromagnetic material, and the magnetizationof the other ferromagnetic layer F is set to be capable of being easilyrotated by an external magnetic field (a signal magnetic field or thelike). Then, only the magnetization of the ferromagnetic layer F can berotated by the external magnetic field to change a relative anglebetween the magnetization directions of the two ferromagnetic layers Pand F to obtain a large magnetoresistance effect (see Phys. Rev. B45,806 (1992), J. Appl. Phys. 69, 4774 (1991)).

[0011] The ferromagnetic layer F is often called a “free layer”, a“magnetic field receiving layer”, or a “magnetization free layer”. Theferromagnetic layer P is often called a “pinned layer” or a“magnetization fixed layer”. The non-magnetic layer S is often called a“spacer layer”, a “non-magnetic intermediate layer” or an “intermediatelayer”.

[0012] The spin-valve film can rotate the magnetization of the freelayer, i.e., the ferromagnetic layer F. Therefore, the spin-valve filmcan be sensitized, so that it is suitable for an MR element for use inan MR head.

[0013] It is required to cause a “sense current” to flow through such aspin-valve element in order to detect the variation in resistance due toa magnetic field.

[0014]FIG. 20 is a conceptual drawing showing a generally used currentsupply system. That is, at present, there is generally used a system forproviding electrodes EL, EL on both ends of a spin-valve element asshown in the figure to cause a sense current I to flow in parallel tothe plane of the film to measure a resistance in a direction parallel tothe plane of the film. This method is generally called a“current-in-plane (CIP)” system.

[0015] In the case of the CIP system, it is possible to obtain a valueof about 10 to 20% as a rate of change in MR. In a shield-type MR headwhich is generally used at present, a spin-valve element has asubstantially square shape, so that the resistance of an MR element issubstantially equal to a value of plane electric resistance (sheetresistance) of an MR film. Therefore, a spin-valve film of a CIP systemcan obtain good S/N characteristics if the value of plane electricresistance is set to be 10 to 30 Ω. This can be relatively simplyrealized by decreasing the thickness of the whole spin-valve film.Because of these advantages, the spin-valve film of the CIP system isgenerally used as an MR element for an MR head at present.

[0016] However, it is expected that the rate of change in MR is requiredto exceed 30% in order to realize information reproduction at a highrecording density exceeding 100 Gbit/inch². On the other hand, it isdifficult to obtain a value exceeding 20% as the rate of change in MR inconventional spin-valve films. For that reason, in order to furtherimprove a recording density, it is a great technical theme to increasethe rate of change in MR.

[0017] From such a point of view, in order to increase the rate ofchange in MR, there is proposed a spin-valve comprising amagnetic/non-magnetic layer stacked film wherein a pinned layer and afree layer are ferromagnetically coupled in a CIP-spin-valve (CIP-SV)film.

[0018]FIG. 21 is a schematic sectional view of a spin-valve film havingsuch a stacked structure. That is, each of a pinned layer P and a freelayer F has the stacked structure of a ferromagnetic layer and anon-magnetic layer. In the case of this structure, the scattering ofelectrons depending on spin in the magnetic layer/non-magnetic layerinterface in the spin-valve film contributes to the MR effect.Therefore, if the number of the magnetic layer/non-magnetic layerinterface between the pinned layer P and the free layer F is increasedso that a larger number of conduction electrons pass through themagnetic layer/non-magnetic layer interface, it is possible to obtain ahigh rate of change in MR.

[0019] However, in the construction of FIG. 21, since the sense currentI flows in parallel to the stacked structure although the number ofinterfaces increases, there is a strong probability that each ofelectrons will flow through any one of the layers, so that the number ofelectrons crossing the interface can not be so increased. Therefore, itis difficult to improve the high rate of change in resistance.

[0020] In addition, in the above described method, since the totalthickness of the film increases by the non-magnetic layers which arestacked on the pinned layer P and free layer F, respectively, the valueof resistance of the plane of the film, i.e., a so-called value of planeelectric resistance (sheet resistance), greatly decreases, so that thevalue of change in resistance (=value of plane electric resistance×rateof change in MR) decreases. Since the output of the head is generally inproportion to the amount of change in resistance, there is also aproblem in that the absolute value of the output decreases when it isactually used as a sensor.

[0021] For the above described reasons, also in the CIP-SV film havingthe multi-layer structure of pin and free layers shown in FIG. 21, it issubstantially difficult to realize a high rate of change in MR exceeding20% and a practical amount of chamber in resistance of 5 to 30 Ω.

[0022] On the other hand, as a method for obtaining a large MR exceeding30%, there is proposed a magnetoresistance effect element (which will behereinafter referred to as a CPP-artificial lattice) of a type (currentperpendicular to plane (CPP)) that a sense current is caused to flow ina direction perpendicular to the plane of the film in an artificiallattice wherein magnetic and non-magnetic materials are stacked.

[0023]FIG. 22 is a conceptual drawing showing a cross-sectionalstructure of a CPP-artificial lattice type element. In amagnetoresistance effect element of this type, electrodes EL areprovided on the top and bottom face of an artificial lattice SLcomprising ferromagnetic/non-magnetic layers, and a sense current Iflows in a direction perpendicular to the plane of the film. It is knownthat this construction can a good interface effect and a high rate ofchange in MR since there is a strong probability that the current I willcross the magnetic layer/non-magnetic layer interface.

[0024] However, in such a CPP artificial lattice type element, it isrequired to measure the electric resistance of an artificial lattice SLhaving the stacked structure of very thin metallic films in a directionperpendicular to the plane of the film. However, this value ofresistance is generally very small. Therefore, in the CPP artificiallattice, it is an important technical theme to increase the value ofresistance. Conventionally, in order to increase this value, it isnecessary to decreases the junction area between the artificial latticeSL and the electrode SL as small as possible and to increase the numberof stacked layers of the artificial lattice SL to increase the totalthickness of the film. For example, when the element is patterned so asto have a size of 0.1 μm×0.1 μm, if a Co layer having a thickness of 2nm and a Cu layer having a thickness of 2 nm are alternately stacked tentimes, the total thickness of the film is 20 nm, and a value ofresistance of about 1 Ω can be obtained.

[0025] For the above described reasons, in order that the CPP artificiallattice type film provides a sufficient head output to be used as a goodreading sensor for a hard disk, it is necessary for the film to be theartificial lattice type, not the spin-valve type, from the standpoint ofresistance.

[0026] However, when the MR element is used for an MR head, it isrequired to cause each of magnetic layers to be a single magnetic domainso as not to generate Barkhausen noises, while controlling themagnetization of the magnetic layer so that an external magnetic fieldcan be efficiently measured. However, as described above, it is requiredto alternately stack many magnetic and non-magnetic layers in order toincrease the value of resistance in the CPP-MR element, and it istechnically very difficult to individually control the magnetization ofsuch many magnetic layers.

[0027] In addition, when the MR element is used for an MR head, it isrequired to allow the magnetization against a small signal magneticfield to sensitively rotate to obtain a high rate of change in MR. Forthat purpose, it is required to improve the signal magnetic flux densityat a sensing portion to obtain a large amount of rotation ofmagnetization even at the same magnetic flux density. Therefore, it isrequired to decrease the total Mst (magnetization×thickness) of layerswherein magnetization is rotated by an external magnetic field. However,in the CPP-MR element, it is required to alternately stack many magneticand non-magnetic layers in order to increase the value of resistance.Therefore, Mst increases, so that it is difficult to improve thesensitivity to the signal magnetic flux.

[0028] For that reason, although it is expected that the CPP artificiallattice type film has a rate of change in MR exceeding 30%, it isdifficult to sensitize the film in order to use the film as an MR sensorfor a head, so that it is substantially impossible to use the film asthe MR sensor.

[0029] On the other hand, it is considered that the spin-valve structureusing FeMn/NiFe/Cu/NiFe, FeMn/CoFe/Cu/CoFe or the like adopts the CPPsystem.

[0030]FIG. 23 is a conceptual drawing showing a cross-sectionalstructure of a CPP-SV element. However, in such a CPP-SV construction,the thickness of a magnetic layer must be increased to about 20 nm inorder to the value of resistance. Also in that case, it is predictedthat the rate of change in resistance would be only about 30% at 4.2 Kand about 15%, which is half thereof, at room temperatures.

[0031] That is, in the spin-valve film of the CPP system, the rate ofchange in MR is only about 15%, and the Mst of the free layer must beincreased. Therefore, it is difficult to sensitize the film in order touse the film as an MR sensor for a head, so that it is substantiallydifficult to use the film.

[0032] As described above, although there are proposed various systems,such as the spin-valve film of the CIP system, the artificial lattice ofthe CPP system, and the spin-valve of the CPP system, it is difficult torealize a spin-valve film which can be used at a high packing densityexceeding 100 Gbit/inch², which has an appropriate value of resistanceand a large amount of change in MR and which is magnetically sensitive,at present.

SUMMARY OF THE INVENTION

[0033] It is therefore an object of the present invention to eliminatethe aforementioned problems and to provide a practical magnetoresistanceeffect element which has an appropriate value of resistance, which canbe sensitized and which has a small number of magnetic layers to becontrolled, while effectively utilizing the scattering effect dependingon spin, and a magnetic head and magnetic recording and/or reproducingsystem using the same.

[0034] In order to accomplish the aforementioned object, according toone aspect of the present invention, a magnetoresistance effect elementcomprises: a magnetization fixed layer in which the direction ofmagnetization is substantially fixed to one direction; a magnetizationfree layer in which the direction of magnetization varies in response toan external magnetic field; and a non-magnetic intermediate layerprovided between the magnetization fixed layer and the magnetizationfree layer, at least one of the magnetization fixed layer and themagnetization free layer having a stacked body in which ferromagneticlayers and non-magnetic layers are alternately stacked, the non-magneticlayers in the stacked body being thinner than the non-magneticintermediate layer, the resistance of the magnetoresistance effectelement varying in response to a relative angle between the direction ofmagnetization of the magnetization fixed layer and the direction ofmagnetization of the magnetization free layer, and a sense current beingapplied to the magnetization fixed layer, the non-magnetic intermediatelayer and the magnetization free layer in a direction substantiallyperpendicular to surfaces of those layers.

[0035] The ferromagnetic layers in the stacked body may beferromagnetically coupled to each other.

[0036] At least one of the ferromagnetic layers included in the stackedbody may include a layer of a first ferromagnetic material, and a layerof a second ferromagnetic material different from the firstferromagnetic material.

[0037] The stacked body may include the ferromagnetic layers of a firstferromagnetic material, and the ferromagnetic layers of a secondferromagnetic material different from the first ferromagnetic material.

[0038] The ferromagnetic layers included in the stacked body may containany one of an iron (Fe) base alloy, a cobalt (Co) base alloy and anickel (Ni) base alloy, and the non-magnetic layers included in thestacked body may contain any one of gold (Au), silver (Ag), copper (Cu),rhodium (Rh), ruthenium (Ru), manganese (Mn), chromium (Cr), rhenium(Re), osmium (Os), iridium (Ir), and an alloy containing any one ofgold, silver, copper, rhodium, ruthenium, manganese, chromium, rhenium,osmium, and iridium.

[0039] Each of the magnetization fixed layer and the magnetization freelayer may have the stacked body, and the stacked body of themagnetization fixed layer may have a different film structure from thatof the stacked body of the magnetization free layer.

[0040] According to another aspect of the present invention, amagnetoresistance effect element comprises: a magnetization fixed layerin which the direction of magnetization is substantially fixed to onedirection; a magnetization free layer in which the direction ofmagnetization varies in response to an external magnetic field; and anon-magnetic intermediate layer provided between the magnetization fixedlayer and the magnetization free layer, at least one of themagnetization fixed layer and the magnetization free layer having astacked body in which two kinds or more of ferromagnetic layers arestacked, the resistance of the magnetoresistance effect element varyingin response to a relative angle between the direction of magnetizationof the magnetization fixed layer and the direction of magnetization ofthe magnetization free layer, and a sense current for detecting thevariation in the resistance being applied to the magnetization fixedlayer, the non-magnetic intermediate layer and the magnetization freelayer in a direction substantially perpendicular to surfaces of thoselayers.

[0041] In any one of the above described magnetoresistance effectelements, at least one of the ferromagnetic layers included in thestacked body may contain an iron (Fe) base alloy.

[0042] At least one of the ferromagnetic layers included in the stackedbody may be formed of an alloy containing nickel (Ni), iron (Fe) orcobalt (Co).

[0043] Each of the magnetization fixed layer and the magnetization freelayer may have the stacked body, and the stacking period in the stackedbody of the magnetization fixed layer may be different from the stackingperiod in the stacked body of the magnetization free layer.

[0044] The non-magnetic intermediate layer may have a stacked bodywherein two kinds or more of non-magnetic layers are stacked.

[0045] The two kinds or more of non-magnetic layers may include twokinds of non-magnetic layers, each of which contains two of gold (Au),silver (Ag), copper (Cu), rhodium (Rh), ruthenium (Re), manganese (Mn),chromium (Cr), rhenium (Re), osmium (Os) and iridium (Ir) as principalcomponents.

[0046] Each of the magnetization fixed layer and the magnetization freelayer may have the stacked body, and the stacked body of themagnetization fixed layer may have a different film structure from thatof the stacked body of the magnetization free layer.

[0047] A magnetic head according to another aspect of the presentinvention may have any one of the above described magnetoresistanceeffect elements.

[0048] A magnetic recording and/or reproducing system according toanother aspect of the present invention may have the above describedmagnetic head, and can read magnetic information stored in a magneticrecording medium.

[0049] The magnetoresistance effect element according to the presentinvention can effectively utilize the scattering effect depending onspin to have both a high rate of change in MR and an appropriate valueof resistance.

BRIEF DESCRIPTION OF THE DRAWINGS

[0050] The present invention will be understood more fully from thedetailed description given herebelow and from the accompanying drawingsof the embodiments of the invention. However, the drawings are notintended to imply limitation of the invention to a specific embodiment,but are for explanation and understanding only.

[0051] In the drawings:

[0052]FIG. 1 is a conceptual drawing showing a cross-sectional structureof the first embodiment of a magnetoresistance effect element accordingto the present invention;

[0053]FIG. 2 is a conceptual drawing showing a cross-sectional structureof a magnetoresistance effect element wherein pin holes are formed innon-magnetic layers FN and PN;

[0054]FIG. 3 is a conceptual drawing showing a cross-sectional structureof a magnetoresistance effect element wherein ferromagnetic layers FFand PF are formed in the form of islands;

[0055]FIG. 4 is a conceptual drawing showing a cross-sectional drawingof a magnetoresistance effect element which uses a stacked film of twokinds of ferromagnetic materials;

[0056]FIG. 5 is a conceptual drawing showing a cross-sectional structureof a magnetoresistance effect element which is formed of two kinds ormore of ferromagnetic materials;

[0057]FIG. 6 is a conceptual drawing showing a cross-sectional structureof a magnetoresistance effect element wherein a bcc ferromagneticmaterial and an fcc ferromagnetic material are combined;

[0058]FIG. 7 is a conceptual drawing showing an example of a spin-valveelement wherein the stacking period in a pinned layer is different fromthe stacking period of a free layer;

[0059]FIG. 8A is a conceptual drawing showing modulation of potential inthe spin-valve element of FIG. 7 when the magnetization of the pinnedlayer is parallel to the magnetization of the free layer;

[0060]FIG. 8B is a conceptual drawing showing modulation of potential inthe spin-valve element of FIG. 7 when the magnetization of the pinnedlayer is anti-parallel to the magnetization of the free layer;

[0061]FIG. 9 is a conceptual drawing showing a cross-sectional structureof a magnetoresistance effect element wherein a non-magnetic layer has astacked structure;

[0062]FIG. 10 is a conceptual drawing showing a spin-valve elementwherein a non-magnetic intermediate layer S comprises multiple layers;

[0063]FIG. 11 is a conceptual drawing showing a cross-sectionalconstruction of a spin-valve element having a synthetic structure;

[0064]FIG. 12 is a conceptual drawing showing a cross-sectionalstructure of a magnetoresistance effect element having a buffer layerand a protective layer;

[0065]FIG. 13 is a conceptual drawing showing a cross-sectionalstructure of the second embodiment of a magnetoresistance effect elementaccording to the present invention;

[0066]FIG. 14 is a conceptual drawing showing an example of a case wherea free layer has three kinds of ferromagnetic layers;

[0067]FIG. 15 is a conceptual drawing showing a cross-sectionalconstruction of a first example of a spin-valve element according to anaspect of the present invention;

[0068]FIG. 16 is a schematic perspective view of a magnetic headincluding a magnetoresistance effect element according to an aspect ofthe present invention;

[0069]FIG. 17 is a perspective view of a principal part illustrating aschematic construction of a magnetic recording and/or reproducing systemaccording to another aspect of the present invention;

[0070]FIG. 18 is an enlarged perspective view of a magnetic headassembly in front of an actuator arm 155, viewed from the side of adisk;

[0071]FIG. 19 is a conceptual drawing illustrating a schematiccross-sectional structure of a spin-valve film;

[0072]FIG. 20 is a conceptual drawing showing a generally used currentsupply system;

[0073]FIG. 21 is a conceptual drawing showing a spin-valve wherein eachof a pinned layer and free layer comprises a ferromagnetically coupledmagnetic/nonmagnetic layer stacked film;

[0074]FIG. 22 is a conceptual drawing showing a cross-sectionalstructure of a CPP-artificial lattice type element; and

[0075]FIG. 23 is a conceptual drawing showing a cross-sectionalconstruction of a CPP-SV element.

DESCRIPTION OF THE EMBODIMENTS

[0076] Referring now to the accompanying drawings, the embodiments ofthe present invention will be described below.

[0077] (First Embodiment)

[0078]FIG. 1 is a conceptual drawing showing a cross-sectional structureof the first embodiment of a magnetoresistance effect element accordingto an aspect of the present invention. That is, the magnetoresistanceeffect element 10A according to the aspect of the present inventioncomprises an antiferromagnetic layer A, a first magnetic material P, anintermediate non-magnetic layer S and a second magnetic material F whichare stacked on a predetermined substrate (not shown) in that order.

[0079] Moreover, electrode layers EL are provided on the top and bottomfaces of this stacked structure, respectively, and a sense current I iscaused to flow in a direction perpendicular to the plane of the film.

[0080] In this embodiment, the first magnetic layer P functions as a“pinned layer”, the magnetization of which is fixed by one-directionalanisotropy due to the antiferromagnetic layer A. In addition, the secondmagnetic layer F functions as a “magnetic field receiving layer” or“free layer”, the magnetization of which is rotated by an externalmagnetic field (e.g., a signal magnetic field) produced from a magneticrecording medium (not shown).

[0081] In this embodiment, the first magnetic layer P and the secondmagnetic layer F have stacked structures of ferromagnetic layerPF/non-magnetic layer PN and ferromagnetic layer FF/non-magnetic layerFN, respectively. In this stacked layer of ferromagneticlayer/non-magnetic layer, the ferromagnetic layers are ferromagneticallycoupled to each other, and magnetization behaves so as to besubstantially integrated. That is, the magnetization of each of theferromagnetic layers included in this stacked structure of ferromagneticlayer/non-magnetic layer is substantially parallel to each other, themagnetization in the pinned layer P being substantially fixed in thesame direction, and the magnetizing direction in the free layer F beingsubstantially the same direction corresponding to the external magneticfield.

[0082] In this embodiment, a larger number of interfaces offerromagnetic layers/non-magnetic layers can be clearly provided in thepinned layer P and free layer F than the CPP spin-valve constructionillustrated in FIG. 23. In the CPP spin-valve film, the scatteringeffect of electron in the interface of ferromagnetic layer/non-magneticlayer, i.e., an interface resistance, has a large spin dependency andhas the function of increasing the CPP-MR.

[0083] In addition, since the interface resistance has a relativelylarge value, the value of resistance in a direction perpendicular to theplane of the film can be increased by increasing the number of theinterfaces of ferromagnetic layers/non-magnetic layers. According to anaspect of the present invention, it is possible to utilize a largernumber of values of interface resistance, and it is possible to providea CPP-SV having a higher resistance and higher rate of change in MR thanthose of the CPP spin-valve film illustrated in FIG. 23.

[0084] In addition, since an aspect of the present invention adopts theCPP system wherein a current I flows in a direction perpendicular to theplane of the film, all of current components cross the interfaces offerromagnetic layers/non-magnetic layers, so that it is possible to veryeffectively utilize the interface effect which can not effectively beutilized in the case of the CIP system illustrated in FIGS. 20 and 21.For that reason, it is possible to very conspicuously obtain thefunction of increasing the rate of change in MR which can notsufficiently be obtained by the CIP construction.

[0085] Moreover, since a sense current I flows in a directionperpendicular to the plane of the film according to an aspect of thepresent invention, there is no problem in that the value of resistanceis lowered by sandwiching the non-magnetic layer like the CIP systemillustrated in FIG. 21.

[0086] As described above, according to an aspect of the presentinvention, it is possible to provide a CPP spin-valve element suitablyutilizing an interface resistance and having an appropriate value ofresistance though it has a spin-valve construction.

[0087] In addition, in this embodiment, since the magnetization of thepinned layer P and the magnetization of the free layer F are operated soas to be integrated, the magnetization can be controlled only by themagnetization fixing of the pinned layer P and the control of themagnetization of one free layer F. As a result, when the element is usedfor a reading sensor, such as a magnetic head, it is possible to realizea magnetic head wherein Barkhausen noises are suppressed.

[0088] In addition, in this embodiment, it is possible to obtain a goodvalue of resistance and a good rate of change in MR while the totalthickness of the pinned layer P and free layer F is small. That is, ascompared with the simple CPP spin-valve construction illustrated in FIG.23, it is possible to sufficiently utilize the interface resistance inthis construction. Therefore, even if the total Mst of the pinned layerP and free layer F is small, it is possible to obtain a sufficient valueof resistance and a sufficient rate of change in MR. Specifically,although the thickness of the magnetic material of the pinned layer Pand free layer F must be about 20 nm in the construction of FIG. 23, itis possible to sufficient characteristics in this construction even ifthe total thickness of the magnetic layer is about 5 nm. Thus, the Mstof the free layer F can be held to be a small value, so that it ispossible to form a sensitive spin-valve element. In addition, since itis possible to decrease the Mst of the pinned layer P, it is possible toimprove the magnetization fixing characteristics by theantiferromagnetic layer, and it is possible to thermally make it stable,so that it is possible to improve the reliability of the device.

[0089] In this embodiment, the ferromagnetic layers included in thefirst and second ferromagnetic layer/non-magnetic layer stackedstructure may be formed of, e.g., a simple substance of Co (cobalt), aCo containing ferromagnetic material such as a Co containing magneticalloy, an Ni base alloy such as NiFe (ferronickel), or an Fe base alloy.

[0090] In this embodiment, it is desired to obtain a high interfaceresistance depending on spin in the interface of ferromagneticlayer/non-magnetic layer. As such a combination of ferromagnetic andnon-magnetic layers, the ferromagnetic layer is preferably formed of anFe base alloy, a Co base alloy or an Ni base alloy, and the non-magneticlayer is preferably formed of Cu (copper), Ag (silver), Au (gold) or analloy thereof.

[0091] In particular, any one of non-ferromagnetic transition metals,such as Rh (rhodium), Ru (ruthenium), Mn (manganese), Cr (chromium), Re(rhenium), Os (osmium) and Ir (iridium), are preferably used. Amongthese transition metals, Mn or Re is more preferably used.

[0092] As a combination in which the interface resistance isparticularly high, any one of Fe base alloy/Au, Fe base alloy/Ag, Febase alloy/Au-Ag alloy, Co base alloy/Cu, Co base alloy/Ag, Co basealloy/Au, and Co base alloy/Cu—Ag—Au alloy is preferably used.

[0093] The thickness of the ferromagnetic layers included in the stackedstructure of ferromagnetic layer/non-magnetic layer is preferably asthin as possible, in order to increase the number of interfaces withoutincreasing the total Mst. In a combination in which magnetization isheld, the magnetic layer may be formed of a monatomic layer. As such acombination, an artificial lattice comprising Fe monatomic layer/Aumonatomic layer may be used. Although the upper limit of the thicknessis not particularly defined, the thickness is preferably 2 nm or less inorder to increase the number of interfaces.

[0094] The thickness of the non-magnetic layer included in the stackedstructure of ferromagnetic layer/non-magnetic layer is preferably 1 nmor less since the ferromagnetic coupling of ferromagnetic layers to eachthere must be strong and stable. However, the thickness is preferablyselected in accordance with the material of the non-magnetic layer sothat the ferromagnetic coupling is stable. Even if the non-magneticlayer is a monoatomic layer as the lower limit, the interface resistancecan be produced.

[0095] In order to suitably obtain the interface resistance, thecombination of materials forming the stacked structure of ferromagneticlayer/non-magnetic layer is preferably a combination wherein theferromagnetic and non-magnetic layers are non-solid-solution systems.However, the present invention should not always be limited tocombinations of non-solid-solution systems.

[0096] The stacked structure of ferromagnetic layer/non-magnetic layeris preferably flat and continuous. However, in order to obtain a goodferromagnetic coupling, there is no problem if the pin holes H areformed in the non-magnetic layers FN and PN as shown in FIG. 2 and ifadjacent ferromagnetic layers FF and PF are connected directly to eachother in that portion.

[0097] Conversely, even if the stacked structure is formed so that theferromagnetic layers FF and PF are arranged in the form of islands asshown in FIG. 3, if the interface of ferromagnetic layer/non-magneticlayer extends substantially in parallel to the plane of the film, thereis no problem.

[0098] The ferromagnetic layer in the stacked structure of ferromagneticlayer/non-magnetic layer is not always required to be formed of one kindof material.

[0099] In the construction illustrated in FIG. 4, a stacked film of twokinds of ferromagnetic materials. That is, ferromagnetic layers PFconstituting a first ferromagnetic layer P constitute a stackedconstruction of PF1/PF2/PF1, and ferromagnetic layers FF constituting asecond ferromagnetic layer F constitute a stacked construction ofFF1/FF2/FF1.

[0100] More specifically, for example, in the pinned layer P, an Fe/Auinterface having a high interface resistance is preferably used.However, since Fe has a large fluctuation in spin, it is desired toinhibit the fluctuation in spin, in order to use it at roomtemperatures. For that reason, the ferromagnetic layer PF preferably hasthe stacked structure of Fe and a magnetic material, which has a smallfluctuation in spin, such as Fe/CoFe/Fe or Fe/NiFe/Fe.

[0101] On the other hand, the Fe/Au interface having a high interfaceresistance is preferably used for the free layer F. However, it isdifficult to obtain magnetically soft characteristics, which arerequired for the free layer, by only Fe. Therefore, the ferromagneticlayers FF preferably have the stacked structure of Fe and a magneticmaterial, which has excellent magnetically soft characteristics, such asFe/CoFe/Fe or Fe/NiFe/Fe.

[0102] Furthermore, in FIG. 4, a high conductive layer G of Cu, Ag, Auor the like is stacked on the free layer F.

[0103] On the other hand, the ferromagnetic layer in the stackedstructure of ferromagnetic layer/non-magnetic layer is not alwaysrequired to be formed of one kind of material. As shown in FIG. 5, theferromagnetic layer may be two or more kinds of ferromagnetic materials.For example, although an Fe/Au interface having a high interfaceresistance is preferably used in the free layer F which is providedbetween the high conductive layer G and the non-magnetic intermediatelayer S, it is difficult to obtain magnetically soft characteristics,which are required for the free layer, by only the ferromagnetic layerFF1 of Fe. For that reason, it is possible to improve magnetically softcharacteristics by adding the ferromagnetic layer FF2 of a magneticmaterial having excellent magnetically soft characteristics, such asCoFe or NiFe, which is ferromagnetically coupled as a ferromagneticlayer.

[0104] In addition, when the ferromagnetic layer in the stackedstructure of ferromagnetic layer/non-magnetic layer contains Fe or an Febase alloy, it preferably has the face-centered cubic (fcc) structure.Because the stacked structure can be more stable when an fcc metal, suchas Au, Ag or Cu, which constitutes the non-magnetic layer, is stackedand because the stacked structure can have good crystalline propertiesas a whole to improve magnetically soft characteristics and reducefluctuation in spin. However, the body-centered cubic (bcc) structurecan also be used.

[0105] When two or more kinds of ferromagnetic layers are combined asillustrated in FIGS. 4 and 5, a ferromagnetic material having the fccstructure can be combined with a ferromagnetic material having the bccstructure. In such a combination, the state of electrons, the shape ofthe Fermi surface, and the distribution of state density of the fccferromagnetic material are greatly different from those of the bccferromagnetic material. For that reason, it is possible to obtain aconsiderable screen effect with respect to conduction electrons, so thatit is possible to obtain a high resistance and a high rate of change inMR.

[0106]FIG. 6 is a conceptual drawing showing an example of a combinationof a bcc ferromagnetic material with an fcc ferromagnetic material. Thatis, in a spin-valve shown in this figure, a first magnetic layer P hasthe stacked structure of ferromagnetic layers PF having the bccstructure and non-magnetic layers PN, and a second magnetic layer F hasthe stacked structure of ferromagnetic layers FF having the fccstructure and non-magnetic layers FN. Thus, even if the ferromagneticlayers of the pinned layer P and free layer F have different crystalstructures, it is possible to obtain a large screen effect.

[0107] In each of the above described magnetic layers, the Fe base alloyis preferably a material, which can easily obtain magnetically softcharacteristics, such as Fe, FeNi, FeCo, FeSi, FeMo or FeAl.

[0108] The Co containing alloy is an alloy of Co, to which one or moreof Fe, Ni, Au, Ag, Cu, Pd, Pt, Ir, Rh, Ru, Os and Hf are added. Theamount of the additional element is preferably in the range of from 5 to50 at %, and more preferably in the range of from 8 to 20 at %. Becausethere is the possibility that the bulk effect does not sufficientlyincrease if the amount of the additional element is too small and thatthe interface effect greatly decreases if the amount of the additionalelement is too large. In order to obtain a high rate of change in MR,the additional element is preferably Fe.

[0109] By the way, in the CPP-SV, the scattering of electrons occurswhen conductive electrons pass through the pinned layer P and the freelayer F, respectively. If the pinned layer P or the free layer F ismultilayered according to an aspect of the present invention, themodulation of band potential based on the staked period of themultilayered structure is carried out. Therefore, if the stacking periodin the pinned layer is different from that in the free layer, the“screen effect” of electrons can be obtained.

[0110]FIG. 7 is a conceptual drawing showing an example of a spin-valveelement wherein the stacking period in a pinned layer is different fromthe stacking period in a free layer.

[0111]FIGS. 8A and 8B are conceptual drawings showing modulation ofpotential in this spin-valve element. That is, FIG. 8A is a graphshowing potentials sensed by electrons in the cases of up-spin anddown-spin when the magnetization of the pinned layer is parallel to themagnetization of the free layer, and FIG. 8B is a graph showingpotentials sensed by electrons in the cases of up-spin and down-spinwhen the magnetization of the pinned layer is anti-parallel to themagnetization of the free layer.

[0112] In the example shown in FIG. 7, the stacking period offerromagnetic layer/non-magnetic layer in the first magnetic layer(pinned layer) P is shorter than the stacking period of ferromagneticlayer/non-magnetic layer in the second magnetic layer (free layer) F.

[0113] The wave number vector of electrons flowing in a directionperpendicular to the plane of the film is perturbed in accordance withmodulation of band potential. The perturbed wave number varies inaccordance with the period of the multilayered structure. Therefore, thestacking periods in the pinned layer P and free layer F are changed asillustrated in FIG. 7, it is possible to greatly restrict the wavenumber of electrons capable of passing through both layers. Moreover,since the screen effect itself has the spin dependence effect, it ispossible to hold a high spin dependency while maintaining a lowtransmission probability of electrons as a whole. For that reason, ifthe stacking periods in the pinned layer P and free layer F areintentionally changed, it is possible to form a CPP-SV capable ofrealizing a high rate of change in MR while maintaining a higherresistance.

[0114] In FIGS. 8A and 8B, the axis of ordinates of each graph showspotentials sensed by conductive electrons, and the axis of abscissasshows the position of the spin-valve element in thickness directions.The potential sensed by conductive electrons corresponds to Fermi energywhen the conductive electrons in a metal are approximated by a freeelectron model. As the Fermi wave number on the Fermi surface increases,the Fermi energy increases, and the potential is more deeply sensed. Thedepth of the potential varies in accordance with the kind of the metal,the potential is modulated in thickness directions if the stackedstructure is formed.

[0115] In FIGS. 8A and 8B, the shallow potential portion shows a statethat the number of conductive electrons is small and the Fermi energy islow. On the other hand, the deep potential portion shows a state thatthe number of conductive electrons is large and the Fermi energy ishigh. Since conductive electrons are spin-divided by exchange energy inthe magnetic material, the magnitude of potential sensed by conductiveelectrons in the case of down-spin is different from that in the case ofup-spin.

[0116] Due to the above described effects, the potentials sensed byconductive electrons in the CPP-SV film according to the presentinvention have structures shown in FIGS. 8A and 8B. That is, since thefirst and second magnetic layers have the stacked structure of magneticlayer/non-magnetic layers, the potential sensed by conductive electronsis Clonich-Penny-modulated, and a mini gap is formed in the bandstructure of conductive electrons Since how to form the mini gap isinfluenced by the stacking period, the place of the mini gap to beformed varies if the stacking period in the first magnetic layer isdifferent from the stacking period in the second magnetic layer.

[0117] For that reason, if electrons are caused to flow in such a CPP-SVin a direction perpendicular to the plane of the film, there is a strongprobability that the conduction of electrons is inhibited by the gap, sothat it is possible to restrict the transmission probability ofconductive electrons as a whole.

[0118] In addition, since the depth of the potential sensed byconductive electrons in the case of up-spin is different from that inthe case of down-spin, how to restrict the transmission probability ofconductive electrons depends on spin, so that it is possible to producea large scattering effect depending on spin.

[0119] From the above described effects, it is possible to form a CPP-SVhaving a high resistance and a high rate of change in resistance.

[0120] On the other hand, according to an aspect of the presentinvention, the ferromagnetic layers must be ferromagnetically coupled toeach other in the stacked structure of ferromagnetic layer/non-magneticlayer constituting the pinned layer P and free layer F. For thatpurpose, it is required to form a good stacked structure. In addition,the magnetic characteristics of the pinned layer P and free layer F canbe improved by adjusting the crystal lattice constant in the stackedstructure to be the optimum value.

[0121] Therefore, the non-magnetic layer can also have a stackedstructure, such as Au/Cu/Au, as shown in FIG. 9, so that it is possibleto realize a good lattice constant while realizing a high interfaceresistance and it is possible to obtain good magnetic characteristics.That is, in the example shown in FIG. 9, in the ferromagnetic layerPF/non-magnetic layer PN constituting the first magnetic layer (pinnedlayer) P, the non-magnetic layer PN has such a construction that thesecond non-magnetic layer PN2 is sandwiched between the firstnon-magnetic layers PN1. Similarly in the second magnetic layer (freelayer) F, the non-magnetic layer FN has a sandwich structure that thesecond non-magnetic layer FN2 is sandwiched between the firstnon-magnetic layers FN1.

[0122] In the construction of FIG. 9, the material of the non-magneticintermediate layer S is preferably a material, in which the mean freepath of conductive electrons is long, such as Cu, Au or Ag. By usingsuch a material, electrons can varistically conduct from theferromagnetic layer forming an electrode to the ferromagnetic layer F,so that it is possible to more effectively utilize the scattering effectof electrons depending on spin which is caused by the ferromagneticmaterial. Thus, it is possible to obtain a higher rate of change in MR.Alternatively, the non-magnetic intermediate layer S may be formed of analloy of the above described three elements. In that case, thecomposition is preferably adjusted so that the crystal lattice constantin the stacked structure can be adjusted to be the optimum value.

[0123] On the other hand, the non-magnetic intermediate layer S may bemultilayered.

[0124]FIG. 10 is a conceptual drawing showing a spin-valve elementwherein a non-magnetic intermediate layer S is multilayered. That is, inthe spin-valve element shown in this figure, the non-magneticintermediate layer S has the stacked structure of first non-magneticlayers SN1 and second non-magnetic layers SN2. All of the non-magneticlayers may be formed of a material, such as Cu, Au or Ag. In this case,conductive electrons can also be perturbed by the stacking period of thestacked structure of non-magnetic layer/non-magnetic layer. That is, ifthe stacking period of non-magnetic layer/non-magnetic layer of thenon-magnetic intermediate layer S, and the stacking period of the pinnedlayer p or the free layer F are suitably set, the wave number vector ofelectrons capable of flowing through the whole CPP-SV in a directionperpendicular to the plane of the film can be further restricted, sothat it is possible to form a CPP-SV capable of realizing a higherresistance and a higher rate of change in MR.

[0125] On the other hand, the material of the antiferromagnetic layer Ais preferably a metallic antiferromagnetic material having excellentmagnetization fixing characteristics. Specifically, an antiferromagneticmaterial, such as PtMn, NiMn, FeMn or IrMn, may be used. The thicknessof the antiferromagnetic layer A is preferably as thin as possible fromthe standpoint of electric characteristics. However, if theantiferromagnetic layer A is too thin, the magnetization fixingcharacteristics deteriorate, so that it is required to select such athickness that the blocking temperature does not decrease. For thatreason, the thickness is preferably 5 nm or more.

[0126] On the other hand, in addition to the above describedconstruction, a magnetic layer antiferromagnetically coupled to anotherferromagnetic layer may be added any one or both of the first magneticlayer P and the second magnetic layer F to form a so-called “syntheticantiferromagnetic layer structure”.

[0127]FIG. 11 is a conceptual drawing showing a cross-sectionalconstruction of a spin-valve element having a synthetic structure. Thatis, in the example shown in this figure, each of the pinned layer P andthe free layer F has the synthetic structure of magnetic layersmagnetized in directions shown by arrows in the figure. By forming suchsynthetic structures, the apparent magnetization can be zero in thepinned layer P, so that the magnetization fixing in the pinned layer canbe more stable. In addition, by decreasing the apparent magnetization inthe free layer F, it is possible to obtain a more sensitive response toexternal magnetic field.

[0128] On the other hand, while no special layer has been providedbetween the electrode EL and the spin-valve in the above describedconstruction, other layers may be provided when an actual element isformed.

[0129] In the spin-valve element illustrated in FIG. 12, a buffer layer(underlying layer) B is provided between an electrode EL and anantiferromagnetic layer A for improving smoothness and crystallineproperties. In addition, a protective layer C is provided between thetop electrode EL and the free layer F.

[0130] The buffer layer (underlying layer) B and the protective layer Care preferably formed of a material having a good wetting property, suchas Ta, Ti or Cr, a material having a low electric resistance and astable fcc structure, such as Cu, Au or Ag, or a stacked structurethereof.

[0131] As the first embodiment of the present invention, the spin-valveelement of the CPP type wherein at least one of the pinned layer and thefree layer has the stacked structure of ferromagnetic layers andnon-magnetic layers has been described above.

[0132] (Second Embodiment)

[0133] The second embodiment of the present invention will be describedbelow.

[0134]FIG. 13 is a conceptual drawing showing a cross-sectionalstructure of a magnetoresistance effect element according to the secondembodiment of the present invention. That is, the magnetoresistanceeffect element according to the second embodiment comprises anantiferromagnetic layer A, a first magnetic material P, a non-magneticintermediate layer S, a second magnetic material F and a high conductivelayer G, which are stacked on a predetermined substrate (not shown) inthat order.

[0135] Moreover, electrode layers EL are provided on the top and bottomfaces of this stacked structure, respectively, and a sense current I issupplied in a direction perpendicular to the plane of the film.

[0136] Also in this embodiment, the first magnetic layer P functions asa “pinned layer”, the magnetization of which is fixed by one-directionalanisotropy due to the antiferromagnetic layer A. In addition, the secondmagnetic layer F functions as a “magnetic field receiving layer” or“free layer”, the magnetization of which is rotated by an externalmagnetic field (e.g., a signal magnetic field) produced from a magneticrecording medium (not shown).

[0137] In this embodiment, the first magnetic layer P or the secondmagnetic layer F has the stacked structure of ferromagnetic layers andnon-magnetic layers. That is, in the embodiment shown in FIG. 13, thepinned layer P has the stacked structure of first ferromagnetic layersPN1 and second ferromagnetic layers PN2, and the free layer F has thestacked structure of first ferromagnetic layers FF1 and secondferromagnetic layers FF2.

[0138] In the stacked layer of ferromagnetic layer/non-magnetic layer inthis embodiment, the ferromagnetic layers are ferromagnetically coupledto each other, and magnetization behaves so as to be substantiallyintegrated. That is, the magnetization of each of the ferromagneticlayers included in this stacked structure of ferromagneticlayer/ferromagnetic layer is substantially parallel to each other, themagnetization in the pinned layer P being substantially arranged in thesame direction, and the magnetizing direction in the free layer F beingsubstantially the same direction with respect to the external magneticfield.

[0139] After the inventor was studied the effects of the interfaceresistance, it was revealed that the effect of the scattering ofelectrons on the interface of ferromagnetic layer/ferromagnetic layer,the interface resistance, in the CPP-SV, has a large spin dependency toserve to increase the CPP-MR.

[0140] In this embodiment, it is possible to provide many interfaces offerromagnetic layer/ferromagnetic layer in the pinned layer P and freelayer F, to utilize a larger number of values of interface resistance,so that it is possible to form a CPP-SV having a high resistance and ahigh rate of change in MR.

[0141] Since the magnetization of the pinned layer P and themagnetization of the free layer F are operated so as to be integrated,the magnetization can be controlled only by the magnetization fixing ofthe pinned layer and the control of the magnetization of one free layer.As a result, when the element is used for a reading sensor, such as ahead, it is possible to form a head of Barkhausen noise free.

[0142] The first and second ferromagnetic layers are formed of, e.g., asimple substance of Co, a Co containing ferromagnetic material such as aCo containing magnetic alloy, a ferromagnetic material such as NiFealloy, or an Fe base alloy.

[0143] As a combination in which the interface resistance isparticularly high, any one of NiFe alloy/CoFe alloy, Fe base alloy/NiFealloy, and Fe base alloy/CoFe alloy is preferably used.

[0144] The thickness of the ferromagnetic layers included in the stackedstructure of ferromagnetic layer/ferromagnetic layer is preferably asthin as possible, in order to increase the number of interfaces withoutincreasing the total Mst. In a combination in which magnetization isheld, the magnetic layer may be formed of a monatomic layer. Althoughthe upper limit of the thickness is not particularly defined, thethickness is preferably 2 nm or less in order to increase the number ofinterfaces.

[0145] The thickness of the magnetic layer included in the stackedstructure of ferromagnetic layer/ferromagnetic layer is preferably 1 nmor less in order to increase the number of interfaces. Even if themagnetic layer is a monoatomic layer as the lower limit, the interfaceresistance can be produced.

[0146] In order to suitably obtain the interface resistance, thecombination of materials forming the stacked structure of ferromagneticlayer/ferromagnetic layer is preferably a combination wherein adjacentferromagnetic layers are non-solid-solution systems. However, thepresent invention should not always be limited to combinations ofnon-solid-solution systems.

[0147] The ferromagnetic layers of the pinned layer P and free layer Fin this embodiment are not always required to be formed of two kinds ofmaterials, but the ferromagnetic layers may be formed of three kinds ormore of ferromagnetic materials.

[0148]FIG. 14 is a conceptual drawing showing an example where a freelayer has three kinds of ferromagnetic layers. That is, in a spin-valveelement shown in this figure, a free layer F has the stacked structureof a first ferromagnetic layer FF1, a second ferromagnetic layer FF2 anda third ferromagnetic layer FF3.

[0149] In the free layer F, the Fe/CoFe interface having a highinterface resistance is preferably used. However, it is difficult toobtain magnetically soft characteristics, which are required for thefree layer, by only Fe. Therefore, the magnetically soft characteristicscan be improved by adding the ferromagnetic layer FF3 having excellentmagnetically soft characteristics, such as NiFe, which isferromagnetically coupled as a ferromagnetic layer.

[0150] When the ferromagnetic layer in the stacked structure offerromagnetic layer/ferromagnetic layer contains Fe or an Fe base alloy,the ferromagnetic layer preferably has the fcc structure. Because thestacked structure can be more stable when an fcc metal, such as CoFe orNiFe, is stacked and because the stacked structure can have goodcrystalline properties as a whole to improve magnetically softcharacteristics and reduce spin fluctuation. However, the bcc structurecan also be used.

[0151] As a combination of two kinds of magnetic materials, a magneticmaterial having the fcc structure can be combined with a magneticmaterial having the bcc structure. In such a combination, the state ofelectrons, the shape of the Fermi surface, and the distribution of statedensity of the fcc magnetic material are greatly different from those ofthe bcc magnetic material. For that reason, it is possible to obtain aconsiderable screen effect with respect to conduction electrons, so thatit is possible to obtain a high resistance and a high rate of change inMR.

[0152] The Fe base alloy is preferably a material, which can easilyobtain magnetically soft characteristics, such as Fe, FeNi, FeCo, FeSi,FeMo or FeAl.

[0153] The Co containing alloy is an alloy of Co, to which one or moreof Fe, Ni, Au, Ag, Cu, Pd, Pt, Ir, Rh, Ru, Os and Hf are added. Theamount of the additional element is preferably in the range of from 5 to50 at %, and more preferably in the range of from 8 to 20 at %. Becausethere is the possibility that the bulk effect does not sufficientlyincrease if the amount of the additional element is too small and thatthe interface effect greatly decreases if the amount of the additionalelement is too large. In order to obtain a high rate of change in MR,the additional element is preferably Fe.

[0154] In the CPP-SV, the scattering of electrons occurs when conductiveelectrons pass through the pinned layer P and the free layer F. If thepinned layer P or the free layer F is multilayered according to thisembodiment, the modulation of band potential based on the staked periodof the multilayered structure is carried out. Therefore, the wave numbervector of electrons capable of flowing in a direction perpendicular tothe plane of the film is restricted in accordance with modulation ofband potential. The restricted wave number varies in accordance with thestacking period. Therefore, also in this embodiment similar to the abovedescribed case referring to FIGS. 7, 8A and 8B, the wave number ofelectrons capable of passing through both layers can be greatlyrestricted by changing the stacking periods in the pinned layer P andfree layer F. Since the screen effect itself has the spin dependenceeffect, it is possible to hold a high spin dependency while maintaininga low transmission probability of electrons as a whole. For that reason,if the stacking periods in the pinned layer P and free layer F areintentionally changed, it is possible to form a CPP-SV capable ofrealizing a high rate of change in MR while maintaining a higherresistance.

[0155] The non-magnetic intermediate layer S is preferably formed of amaterial, in which the mean free path of conductive electrons is long,such as Cu, Au or Ag. By using such a material, electrons canvaristically conduct from the pinned layer P forming an electrode to thefree layer F, so that it is possible to more effectively utilize thescattering effect of electrons depending on spin which is caused by theferromagnetic material. Thus, it is possible to obtain a higher rate ofchange in MR. Alternatively, the non-magnetic intermediate layer S maybe formed of an alloy of the above described three elements. In thatcase, the composition is preferably adjusted so that the crystal latticeconstant in the stacked structure can be adjusted to be the optimumvalue.

[0156] As described above referring to FIG. 10, the non-magneticintermediate layer S may have the stacked structure of non-magneticlayer/non-magnetic layer wherein a material, such as Cu, Au or Ag, isstacked. In this case, if the stacking period of the stacked structureof non-magnetic layer/non-magnetic layer, and the stacking period of thepinned layer p or the free layer F are suitably set, the wave numbervector of electrons capable of flowing through the whole CPP-SV in adirection perpendicular to the plane of the film can be furtherrestricted, so that it is possible to form a CPP-SV capable of realizinga higher resistance and a higher rate of change in MR.

[0157] On the other hand, the antiferromagnetic layer A is preferablyformed of a metallic antiferromagnetic material having excellentmagnetization fixing characteristics. specifically, an antiferromagneticmaterial, such as PtMn, NiMn, FeMn or IrMn, may be used. The thicknessof the antiferromagnetic layer A is preferably as thin as possible fromthe standpoint of electric characteristics. However, if theantiferromagnetic layer A is too thin, the magnetization fixingcharacteristics deteriorate, so that it is required to select such athickness that the blocking temperature does not decrease. For thatreason, the thickness is preferably 5 nm or more.

[0158] In addition to the above described construction, a magnetic layerantiferromagnetically coupled to another ferromagnetic layer may beadded any one or both of the first magnetic layer P and the secondmagnetic layer F to form a synthetic antiferromagnetic layer structureas described above referring to FIG. 11. By forming such a syntheticconstruction, the apparent magnetization can be zero in the pinnedlayer, so that the magnetization fixing in the pinned layer can be morestable. In addition, by decreasing the apparent magnetization in thefree layer, it is possible to obtain a more sensitive response toexternal magnetic field.

[0159] In addition, also in this embodiment similar to the abovedescribed embodiment referring to FIG. 12, a buffer layer (underlyinglayer) B and a protective layer C may be provided. That is, anunderlying layer is preferably formed between the electrode EL and theantiferromagnetic layer A for improving smoothness and crystallineproperties. In addition, a layer to be a protective layer is preferablyarranged between the top electrode EL and the free layer F. Theunderlying layer and the protective layer are preferably formed of amaterial having a good wetting property, such as Ta, Ti or Cr, amaterial having a low electric resistance and a stable fcc structure,such as Cu, Au or Ag, or a stacked structure thereof.

[0160] The embodiment of the present invention has been described above.

[0161] Referring to Examples, the present invention will be describedbelow in more detail.

EXAMPLE 1

[0162]FIG. 15 is a conceptual drawing showing a cross-sectionalconstruction of a spin-valve element according to a first example of thepresent invention. A fabricating process in this example will bedescribed below.

[0163] First, a Cu bottom electrode EL1 having a thickness of 500 nm wasstacked on a thermally oxidized silicon (Si) substrate (not shown) bythe sputtering method, and the Cu bottom electrode EL1 was formed so asto have a stripe shape having a width of 9 μm by the photolithography.Then, a CPP-SV 3 μm square was deposited thereon. The stackedconstruction of the film was as follows. Ta 5 nm/NiFe 2 nm/PtMn 15nm/CoFe 1 nm/ Cu 1 nm/CoFe 1 nm/Cu 1 nm/CoFe 1 nm/ Cu 3 nm/CoFe 1 nm/Cu1 nm/CoFe 1 nm/ Cu 1 nm/CoFe 1 nm/Cu 1 nm/Ta 5 nm

[0164] An insulating film Z of AlOx was deposited thereon, and a hole0.1 μm square was formed in the insulating film Z. Then, a Cu topelectrode EL2 having a thickness of 500 nm was stacked thereon by thesputtering method. In this example, with the above describedconstruction, it was possible to measure the characteristics of theCPP-SV via the hole 0.1 μm square of the insulating film Z.

[0165] As the results of measurement at room temperatures, theresistance was 5 Ω, and it was possible to obtain a rate of change inresistance of 10%. Thus, it was possible to obtain an amount of changein resistance of 0.5 Ω. In addition, it was verified that the pinnedlayer P was suitably magnetization-fixed and that the magnetization ofthe stacked structure constituting the pinned layer P moved integrally.

[0166] It was also verified that Hc of the free layer F was small andits magnetization moved integrally with respect to the external magneticfield.

[0167] In addition, a fine through hole was formed in a portion of Ta 5nm/NiFe 2 nm/PtMn 15 nm constituting the bottom structure of the filmstructure in this example, to cause the Cu bottom electrode to bonddirectly to the CoFe/Cu stacked structure, and the size of the holeformed in the insulating film Z was set to be 0.05 μm square. Thus, itwas possible to measure MR from which a parasitic resistance caused bythe Ta 5 nm/NiFe 2 nm/PtMn 15 nm structure was removed.

[0168] As a result, the resistance was 5 Ω, and it was possible toobtain a rate of change in resistance of 40%. Thus, it was possible toobtain an amount of change in resistance of 2 Ω. In addition, it wasverified that the pinned layer P was suitably magnetization-fixed by theantiferromagnetic layer A and that the magnetization of the stackedstructure constituting the pinned layer P moved integrally.

Comparative Example 1

[0169] As a comparative example to the above described example, aspin-valve element of a CPP type wherein each of a pinned layer and afree layer was a monolayer was fabricated by way of experiment.

[0170] First, a Cu bottom electrode EL1 having a thickness of 500 nm wasstacked on a thermally oxidized silicon (Si) substrate by the sputteringmethod, and the Cu bottom electrode EL1 was formed so as to have astripe shape having a width of 9 μm by the photolithography. Then, aCPP-SV 3 μm square was deposited thereon. The construction of the filmwas as follows.

[0171] Ta 5 nm (buffer layer)/NiFe 2 nm (buffer layer)/PtMn 15 nm(antiferromagnetic layer)/CoFe 3 nm (pinned layer) Cu 3 nm (non-magneticintermediate layer)/CoFe 3 nm (free layer)/Cu 1 nm (high conductivelayer)/CoFe 5 nm (protective layer)

[0172] The same insulating film of AlOx as that shown in FIG. 15 wasformed thereon, and a hole 0.1 μm square was formed in AlOx. Then, a Cutop electrode having a thickness of 500 nm was stacked thereon by thesputtering method. In this example, it was possible to measure thecharacteristics of the CPP-SV via the hole 0.1 μm square of AlOx. As theresults of measurement at room temperatures, the resistance was 3Ω, andthe rate of change in resistance was only 2%. Therefore, the amount ofchange in resistance was only 0.06 Ω. so that the amount of change wasonly about ⅛ as large as that in Example 1.

Comparative Example 2

[0173] As a second comparative example, a spin-valve element of a CPPtype wherein a sense current was caused to flow in a direction parallelto the plane of the film was fabricated by way of experiment.

[0174] First, the same stacked structure as that in the firstcomparative example was formed on a thermally oxidized silicon (Si)substrate by the sputtering method.

[0175] Ta 5 nm (buffer layer)/NiFe 2 nm (buffer layer)/PtMn 15 nm(antiferromagnetic layer)/CoFe 3 nm (pinned layer)/Cu 3 nm (non-magneticintermediate layer)/CoFe 3 nm (free layer)/Cu 1 nm (high conductivelayer)/Ta 5 nm (protective layer)

[0176] Then, electrodes were formed on both end portions of the stackedfilm, and a sense current was caused to flow in a direction parallel tothe plane of the film to measure a rate of change in MR. As a result,the rate of change in MR was 8%.

[0177] Then, a CIP type spin-valve element having the stacked structureof a pinned layer and a free layer was fabricated by way of experiment.The stacked structure was as follows.

[0178] Ta 5 rm (buffer layer)/NiFe 2 nm (buffer layer)/PtMn 15 nm(antiferromagnetic layer)/CoFe 1 nm (pinned layer)/Co 1 nm (pinnedlayer)/CoFe 1 nm (pinned layer)/Cu 1 nm (pinned layer)/CoFe 1 nm (pinnedlayer)/Cu 3 nm (non-magnetic intermediate layer)/CoFe1 nm (freelayer)/Cu 1 nm (free layer)/CoFe 1 nm (free layer)/Cu 1 nm (freelayer)/CoFe 1 nm (free layer)/Cu 1 nm (high conductive layer)/Ta 5 nm(protective layer)

[0179] This stacked structure was deposited to measure a rate of changein MR. As a result, the rate of change in MR was 9%. That is, althoughthe rate of change in MR was increased as compared with ComparativeExample 1, the increased rate was only a small value.

[0180] From the results of the above described comparative examples, itwas revealed that it was not so effective that the pinned layer and thefree layer in the CIP type SV element had the multilayer structure ofthe ferromagnetic layers and the non-magnetic layers.

EXAMPLE 2

[0181] As a second example of the present invention, a CPP typespin-valve element having an Fe/Au type stacked structure will bedescribed below.

[0182] First, a Cu bottom electrode having a thickness of 500 nm wasstacked on a thermally oxidized silicon (Si) substrate by the sputteringmethod, and the Cu bottom electrode was formed so as to have a stripeshape having a width of 9 μm by the photolithography. Then, a CPP-SV 3μm square was deposited thereon. The stacked construction of the filmwas as follows.

[0183] Ta 5 nm (buffer layer)/NiFe 2 nm (buffer layer)/PtMn 15 nm(antiferromagnetic layer)/Fe 1 mm (pinned layer)/Au 1 nm (pinnedlayer)/Fe 1 nm (pinned layer)/Au 1 nm (pinned layer)/Fe 1 nm (pinnedlayer)/Au 3 nm (non-magnetic intermediate layer)/Fe 1 nm (free layer)/Au1 nm (free layer)/Fe 1 nm (free layer)/Au 1 nm (free layer)/Fe 1 nm(free layer)/Au 1 nm (high conductive layer)/Ta 5 nm (protective layer)

[0184] As shown in FIG. 15, an insulating film of AlOx was formedthereon, and a hole 0.1 μm square was formed in AlOx. Then, a Cu topelectrode having a thickness of 500 nm was stacked thereon by thesputtering method. In this example, with the above describedconstruction, it was possible to measure the characteristics of theCPP-SV via the hole 0.1 μm square of AlOx. As the results of measurementat room temperatures, the resistance was 8 Ω, and it was possible toobtain a rate of change in resistance of 20%. Thus, it was possible toobtain an amount of change in resistance of 1.6 Ω.

[0185] In addition, it was verified that the pinned layer was suitablymagnetization-fixed by the antiferromagnetic layer and that themagnetization of the pin stacked structure moved integrally.

[0186] It was also verified that, although Hc of the free layer F was alarge value of 20 Oe, the magnetization moved integrally with respect tothe external magnetic field.

[0187] In addition, a fine through hole was formed in a portion of Ta 5nm/NiFe 2 nm/PtMn 15 nm constituting the bottom structure of the filmstructure in this example, to cause the Cu bottom electrode to bonddirectly to the CoFe/Cu stacked structure, and the size of the holeformed in the insulating film Z was set to be 0.05 μm square. Thus, itwas possible to measure MR from which a parasitic resistance caused bythe Ta 5 nm/NiFe 2 nm/PtMn 15 nm structure was removed.

[0188] As a result, the resistance was 12 Ω, and it was possible toobtain a rate of change in resistance of 40%. Thus, it was possible toobtain an amount of change in resistance of 2 Ω. In addition, it wasverified that the pinned layer P was suitably magnetization-fixed by theantiferromagnetic layer A and that the magnetization of the stackedstructure constituting the pinned layer P moved integrally.

EXAMPLE 3

[0189] As a third example of the present invention, a CPP typespin-valve element which has an Fe/Au type stacked structure and whichis provided with an NiFe layer on a free layer to improve magneticallysoft characteristics will be described below.

[0190] First, a Cu bottom electrode having a thickness of 500 nm wasstacked on a thermally oxidized silicon (Si) substrate by the sputteringmethod, and the Cu bottom electrode was formed so as to have a stripeshape having a width of 9 μm by the photolithography. Then, a CPP-SV 3μm square was deposited thereon. The construction of the film was asfollows.

[0191] Ta 5 nm (buffer layer)/NiFe 2 nm (buffer layer)/PtMn 15 nm(antiferromagnetic layer)/Fe 1 nm (pinned layer)/Au 1 nm (pinnedlayer)/Fe 1 nm (pinned layer)/Au 1 nm (pinned layer)/Fe 1 nm (pinnedlayer)/Au 3 nm (non-magnetic intermediate layer)/Fe 1 nm (free layer)/Au1 nm (free layer)/Fe 1 nm (free layer)/Au 1 nm (free layer)/NiFe 2 nm(free layer)/Ta 5 nm (protective layer)

[0192] As shown in FIG. 15, an insulating film of AlOx was formedthereon, and a hole 0.1 μm square was formed in AlOx. Then, a Cu topelectrode having a thickness of 500 nm was stacked thereon by thesputtering method. Also in this example, with the above describedconstruction, it was possible to measure the characteristics of theCPP-SV via the hole 0.1 μm square of AlOx.

[0193] As the results of measurement at room temperatures, theresistance was 7 Ω, and it was possible to obtain a rate of change inresistance of 18%. Thus, it was possible to obtain an amount of changein resistance of 1.26 Ω.

[0194] In addition, it was verified that the pinned layer was suitablymagnetization-fixed by the antiferromagnetic layer and that themagnetization of the pin stacked structure moved integrally.

[0195] It was also verified that it was possible to decrease Hc of thefree layer to 18 Oe and that the magnetization moved integrally withrespect to the external magnetic field.

[0196] In addition, a fine through hole was formed in a portion of Ta 5nm/NiFe 2 nm/PtMn 15 nm constituting the bottom structure of the filmstructure in this example, to cause the Cu bottom electrode to bonddirectly to the CoFe/Cu stacked structure, and the size of the holeformed in the insulating film Z was set to be 0.05 μm square. Thus, itwas possible to measure MR from which a parasitic resistance caused bythe Ta 5 nm/NiFe 2 nm/PtMn 15 nm structure was removed.

[0197] As a result, the resistance was 10 Ω, and it was possible toobtain a rate of change in resistance of 40%. Thus, it was possible toobtain an amount of change in resistance of 4.0 Ω. In addition, it wasverified that the pinned layer P was suitably magnetization-fixed by theantiferromagnetic layer A and that the magnetization of the stackedstructure constituting the pinned layer P moved integrally.

EXAMPLE 4

[0198] First, a Cu bottom electrode having a thickness of 500 nm wasstacked on a thermally oxidized silicon (Si) substrate by the sputteringmethod, and the Cu bottom electrode was formed so as to have a stripeshape having a width of 9 μm by the photolithography. Then, a CPP-SV 3μm square was deposited thereon. The construction of the film was asfollows.

[0199] Ta 5 nm (buffer layer)/NiFe 2 nm (buffer layer)/PtMn 15 nm(antiferromagnetic layer)/Fe 0.5 nm (pinned layer)/CoFe 0.5 nm (pinnedlayer)/Fe 0.5 nm (pinned layer)/Au 1 nm (pinned layer)/Fe 0.5 nm (pinnedlayer)/CoFe 0.5 nm (pinned layer)/Fe 0.5 nm (pinned layer)/Au 3 nm(pinned layer)/Fe 0.5 nm (free layer)/CoFe 0.5 nm (free layer)/Fe 0.5 nm(free layer)/Au 1 nm (free layer)/Fe 0.5 nm (free layer)/CoFe 0.5 nm(free layer)/ Fe 0.5 nm (pinned layer)/Au 1 nm (free layer)/NiFe 2 nm(free layer)/Ta 5 nm (protective layer)

[0200] As shown in FIG. 15, an insulating film of AlOx was formedthereon, and a hole 0.1 μm square was formed in AlOx. Then, a Cu topelectrode having a thickness of 500 nm was stacked thereon by thesputtering method. In this example, with the above describedconstruction, it was possible to measure the characteristics of theCPP-SV via the hole 0.1 μm square of AlOx.

[0201] As the results of measurement at room temperatures, theresistance was 9 Ω, and it was possible to obtain a rate of change inresistance of 27%. Thus, it was possible to obtain an amount of changein resistance of 2.5 ‘Ω.

[0202] In addition, it was verified that the pinned layer was suitablymagnetization-fixed and that the magnetization of the pin stackedstructure moved integrally. It was also verified that it was possible todecrease Hc of the free layer to 8 Oe, and that the magnetization movedintegrally with respect to the external magnetic field.

[0203] In addition, a fine through hole was formed in a portion of Ta 5nm/NiFe 2 nm/PtMn 15 nm constituting the bottom structure of the filmstructure in this example, to cause the Cu bottom electrode to bonddirectly to the CoFe/Cu stacked structure, and the size of the holeformed in the insulating film Z was set to be 0.05 μm square. Thus, itwas possible to measure MR from which a parasitic resistance caused bythe Ta 5 nm/NiFe 2 nm/PtMn 15 nm structure was removed.

[0204] As a result, the resistance was 20 Ω, and it was possible toobtain a rate of change in resistance of 40%. Thus, it was possible toobtain an amount of change in resistance of 8 Ω. In addition, it wasverified that the pinned layer P was suitably magnetization-fixed by theantiferromagnetic layer A and that the magnetization of the stackedstructure constituting the pinned layer P moved integrally.

EXAMPLE 5

[0205] First, a Cu bottom electrode having a thickness of 500 nm wasstacked on a thermally oxidized silicon (Si) substrate by the sputteringmethod, and the Cu bottom electrode was formed so as to have a stripeshape having a width of 9 μm by the photolithography. Then, a CPP-SV 3μm square was deposited thereon. The construction of the film was asfollows.

[0206] Ta 5 nm (buffer layer)/NiFe 2 nm (buffer layer)/PtMn 15 nm(antiferromagnetic layer)/Fe 1 nm (pinned layer)/CoFe 1 nm (pinnedlayer)/Fe 1 nm (pinned layer)/CoFe 1 nm (pinned layer)/Fe 1 nm (pinnedlayer)/Au 3 nm (non-magnetic intermediate layer)/Fe 1 nm (freelayer)/CoFe 1 nm (free layer)/Fe 1 nm (free layer)/CoFe 1 nm (freelayer)/NiFe 2 nm (free layer)/Ta 5 nm (protective layer)

[0207] As shown in FIG. 15, an insulating film of AlOx was formedthereon, and a hole 0.1 μm square was formed in AlOx. Then, a Cu topelectrode having a thickness of 500 nm was stacked thereon by thesputtering method. In this example, with the above describedconstruction, it was possible to measure the characteristics of theCPP-SV via the hole 0.1 μm square of AlOx.

[0208] As the results of measurement at room temperatures, theresistance was 6 Ω. and it was possible to obtain a rate of change inresistance of 16%. Thus, it was possible to obtain an amount of changein resistance of 0.96 Ω.

[0209] In addition, it was verified that the pinned layer was suitablymagnetization-fixed and that the magnetization of the pin stackedstructure moved integrally.

[0210] It was also verified that it was possible to decrease Hc of thefree layer to 8 Oe and that the magnetization moved integrally withrespect to the external magnetic field.

[0211] In addition, a fine through hole was formed in a portion of Ta 5nm/NiFe 2 nm/PtMn 15 nm constituting the bottom structure of the filmstructure in this example, to cause the Cu bottom electrode to bonddirectly to the CoFe/Cu stacked structure, and the size of the holeformed in the insulating film Z was set to be 0.05 μm square. Thus, itwas possible to measure MR from which a parasitic resistance caused bythe Ta 5 nm/NiFe 2 nm/PtMn 15 nm structure was removed.

[0212] As a result, the resistance was 8 Ω, and it was possible toobtain a rate of change in resistance of 40%. Thus, it was possible toobtain an amount of change in resistance of 3.2 Ω. In addition, it wasverified that the pinned layer P was suitably magnetization-fixed by theantiferromagnetic layer A and that the magnetization of the stackedstructure constituting the pinned layer P moved integrally.

[0213] (Third Embodiment)

[0214] As a third embodiment of the present invention, a magnetic headusing a magnetoresistance effect element according to an aspect of thepresent invention will be described below.

[0215]FIG. 16 is a schematic perspective view of a principal part of amagnetic head using a magnetoresistance effect element according to anaspect of the present invention. That is, the magnetic head according toanother aspect of the present invention has a pair of magnetic yokes102, 102 which are arranged so as to face a recording medium 200. On themagnetic yokes 102, 102, a magnetoresistance effect element 104magnetically coupled thereto is provided. The magnetoresistance effectelement 104 is any one of the CPP type elements according to an aspectof the present invention, which have bee described above referring toFIGS. 1 through 15. On both sides thereof, a pair of bias layers 106,106 are formed so as to straddle the pair of magnetic yokes 102, 102.The bias layers 106 are made of an antiferromagnetic or ferromagneticmaterial, and have the function of directing the magnetization of themagnetic yoke 102 and the free layer of the magnetoresistance effectelement 104 to a direction perpendicular to a recording magnetic field,i.e., to the y direction in the figure.

[0216] In the recording medium 200, a recording track 200 T is formed,and recording bits 200B are arranged. In each of the recording bits200B, a signal magnetization illustrated by arrow is formed. The signalmagnetic flux from these recording bits is given to a magnetic circuitwhich connects the magnetic yokes 102 to the magnetoresistance effectelement 104. If the magnetic field of the recording bit 200B is given tothe magnetoresistance effect element 104, the magnetization of the freelayer rotates on the plane from they direction due to the bias layer106. Then, the variation in magnetizing direction is detected as thevariation in magnetic resistance.

[0217] In order to match the magnetic detection region of themagnetoresistance effect element to the size of the recording bit 200B,the contact of the electrode of the magnetoresistance effect element 104is formed so as to be limited to a region corresponding to a recordingtrack width W shown in the figure.

[0218] According to the embodiment of the present invention, any one ofthe CPP type elements described above referring to FIGS. 1 through 15 isused as the magnetoresistance effect element 104, so that it is possibleto obtain both an appropriate element resistance and a large variationin magnetic resistance. That is, it is possible to realize a magnetichead having a greatly higher sensitive and more stable reliability thanthose of conventional heads.

[0219] While the magnetic head suitable for magnetic recording media ofa longitudinal (in-plane) recording system has been described in thisexample, the present invention should not be limited thereto. Themagnetoresistance effect element according to the present invention maybe applied to a magnetic head suitable for vertical recording media, toobtain the same effects.

[0220] (Fourth Embodiment)

[0221] As a fourth embodiment of the present invention, a magneticrecording and/or reproducing system using a magnetoresistance effectelement according to embodiments of the present invention will bedescribed below. Anyone of the magnetoresistance effect elementsaccording to embodiments of the present invention, which have beendescribed above referring to FIGS. 1 through 15, can be mounted on amagnetic head illustrated in FIG. 16, and can be incorporated in, e.g.,a recording/reproducing integral type magnetic head assembly, to beapplied to a magnetic recording and/or reproducing system.

[0222]FIG. 17 is a perspective view illustrating a schematicconstruction of a principal part of such a magnetic recording and/orreproducing system. That is, a magnetic recording and/or reproducingsystem 150 according to an aspect of the present invention is a systemof a type using a rotary actuator. In this figure, a longitudinalrecording or vertical recording magnetic disk 200 is mounted on aspindle 152, and is rotated in a direction of arrow A by means of amotor (not shown) which responds to a control signal from a drive unitcontrol part (not shown). A head slider 153 for recording/reproducinginformation to be stored in the magnetic disk 200 is mounted on the tipof a thin-film-like suspension 154. For example, a magnetic headincluding any one of the magnetoresistance effect elements according tothe present invention, which have been described in Example 6, isprovided in the vicinity of the tip of the head slider 153.

[0223] If the magnetic disk 200 rotates, the medium facing surface orair bearing surface (ABS) of the head slider 153 is held at apredetermined flying height from the surface of the magnetic disk 200.

[0224] The suspension 154 is connected to one end of an actuator arm 155which has a bobbin portion or the like for holding a driving coil (notshown). On the other hand of the actuator arm 155, a voice coil motor156 which is a kind of a linear motor is provided. The voice coil motor156 comprises: a driving coil (not shown) wound onto the bobbin portionof the actuator arm 155; and a magnetic circuit comprising permanentmagnets, which are arranged so as to face each other via the coil, andfacing yokes.

[0225] The actuator arm 155 is held by two ball bearings (not shown)which are provided above and below a fixing shaft 157, and is rotatableand slidable by means of the voice coil motor 156.

[0226]FIG. 18 is an enlarged perspective view of a magnetic headassembly in front of an actuator arm 155, which is viewed from the sideof a disk. That is, the magnetic head assembly 160 has an actuator arm151 having, e.g., a bobbin portion or the like for holding a drivingcoil, and a suspension 154 is connected to one end of the actuator arm155.

[0227] A head slider 153 having a reproducing magnetic head using amagnetoresistance effect element according to embodiments of the presentinvention is mounted on the tip of the suspension 154. A recording headmay be combined. The suspension 154 has a lead wire 164 for writing andreading signals. This lead wire 164 is electrically connected to eachelectrode of the magnetic head which is incorporated in the head slider153. In the figure, reference number 165 denotes an electrode pad of themagnetic head assembly 160.

[0228] Between the medium facing surface or air bearing surface (ABS) ofthe head slider 153 and the surface of the magnetic disk 200, apredetermined flying height is set.

[0229] The slider 153 including the magnetic head 10 operates whileflying at a predetermined height from the surface of the magnetic disk200. According to an aspect of the present invention, such a “flyingtraveling type” magnetic recording and/or reproducing system can alsoreproduce at low noises with a higher resolution than conventionalsystems.

[0230] On the other hand, of course, a “contact traveling type” magneticrecording and/or reproducing system for traveling the slider whilepositively causing the magnetic head 10 to contact the magnetic disk 200can also reproduce at low noises with a higher resolution thanconventional systems.

[0231] Referring to Examples, the embodiments of the present inventionhave been described. However, the present invention should not belimited to these examples.

[0232] For example, with respect to the structure of the spin-valveelement and the materials of the respective layers, the presentinvention may be similarly applied to all embodiments, which can beselected by persons with ordinary skill in the art, to provide the sameeffects. For example, the present invention can be similarly applied toa “dual type” structure.

[0233] In addition, the structure of the magnetic head, the materialsand shapes of the respective elements constituting the magnetic headshould not be limited to those described above in Examples, but thepresent invention may be similarly applied to all embodiments, which canbe selected by persons with ordinary skill in the art, to provide thesame effects.

[0234] The magnetic recording and/or reproducing system may be areproducing only system or a recording and/or reproducing system. Inaddition, the medium should not be limited to a hard disk, but it may beany one of all magnetic recording media, such as flexible disks andmagnetic cards. Moreover, the magnetic recording and/or reproducingsystem may be a so-called “removable” type system wherein a magneticrecording medium is removed from the system.

[0235] As described above, according to the present invention, it ispossible to provide a magnetoresistance effect element which has anappropriate value of resistance and a large amount of change in MR andwhich is magnetically sensitive.

[0236] As a result, it is possible to surely read magnetic informationfrom a finer recording bit from that in conventional elements, so thatit is possible to greatly improve the packing density of a recordingmedium. Simultaneously, the reliability of the magnetic recording and/orreproducing system is improved due to thermal stability, and theutilized scope thereof is extended, so that there is a great industrialmerit.

[0237] While the present invention has been disclosed in terms of theembodiment in order to facilitate better understanding thereof, itshould be appreciated that the invention can be embodied in various wayswithout departing from the principle of the invention. Therefore, theinvention should be understood to include all possible embodiments andmodification to the shown embodiments which can be embodied withoutdeparting from the principle of the invention as set forth in theappended claims.

What is claimed is:
 1. A magnetoresistance effect element comprising: amagnetization fixed layer in which a direction of magnetization issubstantially fixed to one direction; a magnetization free layer inwhich a direction of magnetization varies in response to an externalmagnetic field; and a non-magnetic intermediate layer provided betweenthe magnetization fixed layer and the magnetization free layer, at leastone of the magnetization fixed layer and the magnetization free layerhaving a stacked body in which ferromagnetic layers and non-magneticlayers are alternately stacked, the non-magnetic layers in the stackedbody being thinner than the non-magnetic intermediate layer, aresistance of the magnetoresistance effect element varying in accordancewith a relative angle between the direction of magnetization of themagnetization fixed layer and the direction of magnetization of themagnetization free layer, and a sense current being flowed to themagnetization fixed layer, the non-magnetic intermediate layer and themagnetization free layer in a direction substantially perpendicular tosurfaces of those layers.
 2. A magnetoresistance effect element as setforth in claim 1, wherein each of ferromagnetic layers in the stackedbody is ferromagnetically coupled.
 3. A magnetoresistance effect elementas set forth in claim 1, wherein at least one of the ferromagneticlayers included in the stacked body includes a layer of a firstferromagnetic material, and a layer of a second ferromagnetic materialdifferent from the first ferromagnetic material.
 4. A magnetoresistanceeffect element as set forth in claim 1, wherein the stacked bodyincludes the ferromagnetic layers of a first ferromagnetic material, andthe ferromagnetic layers of a second ferromagnetic material differentfrom the first ferromagnetic material.
 5. A magnetoresistance effectelement as set forth in claim 1, wherein the ferromagnetic layersincluded in the stacked body contains any one of an iron (Fe) basealloy, a cobalt (Co) base alloy and a nickel (Ni) base alloy, and thenon-magnetic layers included in the stacked body contains any one ofgold (Au), silver (Ag), copper (Cu), rhodium (Rh), ruthenium (Ru),manganese (Mn), chromium (Cr), rhenium (Re), osmium (Os), iridium (Ir),and an alloy containing any one of gold, silver, copper, rhodium,ruthenium, manganese, chromium, rhenium, osmium, and iridium.
 6. Amagnetoresistance effect element as set forth in claim 1, wherein atleast one of the ferromagnetic layers included in the stacked bodycontains an iron (Fe) base alloy.
 7. A magnetoresistance effect elementas set forth in claim 1, wherein each of the magnetization fixed layerand the magnetization free layer has the stacked body, and the stackingperiod in the stacked body of the magnetization fixed layer is differentfrom the stacking period in the stacked body of the magnetization freelayer.
 8. A magnetoresistance effect element as set forth in claim 1,wherein the non-magnetic intermediate layer has a stacked body whereintwo kinds or more of non-magnetic layers are stacked.
 9. Amagnetoresistance effect element as set forth in claim 8, wherein thetwo kinds or more of non-magnetic layers include two kinds ofnon-magnetic layers, each of which contains two of gold (Au), silver(Ag), copper (Cu), rhodium (Rh), ruthenium (Ru), manganese (Mn),chromium (Cr), rhenium (Re), osmium (Os), and iridium (Ir) as principalcomponents.
 10. A magnetoresistance effect element comprising: amagnetization fixed layer in which a direction of magnetization issubstantially fixed to one direction; a magnetization free layer inwhich a direction of magnetization varies response to an externalmagnetic field; and a non-magnetic intermediate layer provided betweenthe magnetization fixed layer and the magnetization free layer, p1 atleast one of the magnetization fixed layer and the magnetization freelayer having a stacked body in which two kinds or more of ferromagneticlayers are stacked, a resistance of the magnetoresistance effect elementvarying in accordance with a relative angle between the direction ofmagnetization of the magnetization fixed layer and the direction ofmagnetization of the magnetization free layer, a sense current beingflowed to the magnetization fixed layer, the non-magnetic intermediatelayer and the magnetization free layer in a direction substantiallyperpendicular to surfaces of those layers.
 11. A magnetoresistanceeffect element as set forth in claim 10, wherein at least one of theferromagnetic layers included in the stacked body contains an iron (Fe)base alloy.
 12. A magnetoresistance effect element as set forth in claim10, wherein at least one of the ferromagnetic layers included in thestacked body is formed of an alloy containing nickel (Ni), iron (Fe) orcobalt (Co).
 13. A magnetoresistance effect element as set forth inclaim 10, wherein the stacked body is any one of an (NiFe alloy/CoFealloy) stacked body, an (Fe base alloy/NiFe alloy) stacked body, and an(Fe base alloy/CoFe alloy) stacked body.
 14. A magnetoresistance effectelement as set forth in claim 10, wherein each of the magnetizationfixed layer and the magnetization free layer has the stacked body, andthe stacking period in the stacked body of the magnetization fixed layeris different from the stacking period in the stacked body of themagnetization free layer.
 15. A magnetoresistance effect element as setforth in claim 10, wherein the non-magnetic intermediate layer has astacked body wherein two kinds or more of non-magnetic layers arestacked.
 16. A magnetoresistance effect element as set forth in claim15, wherein the two kinds or more of non-magnetic layers include twokinds of non-magnetic layers, each of which contains two of gold (Au),silver (Ag) and copper (Cu) as principal components.
 17. A magnetic headhaving a magnetoresistance effect element as set forth in claim
 1. 18. Amagnetic head having a magnetoresistance effect element as set forth inclaim
 10. 19. A magnetic recording and/or reproducing system which has amagnetic head as set forth in claim 17 and which is capable of readingmagnetic information stored in a magnetic recording medium.
 20. Amagnetic recording and/or reproducing system which has a magnetic headas set forth in claim 18 and which is capable of reading magneticinformation stored in a magnetic recording medium.